National Research Center for Career and Technical Education
Transportation, Distribution, and Logistics: Tire and Wheel Assemblies
Is bigger really better? By the end of this lesson, learners will be able to apply formulas for computing the diameter of tires and wheel assemblies. Begin by showing a slide presentation that will review definitions for radius and...
EngageNY
Arcs and Chords
You've investigated relationships between chords, radii, and diameters—now it's time for arcs. Learners investigate relationships between arcs and chords. Learners then prove that congruent chords have congruent arcs, congruent arcs have...
Noyce Foundation
Circular Reasoning
Examine the origin and application of pi in five different levels. The five lessons in the resource begin with an analysis of the relationship between the radius and circumference of a circle. The following lessons lead learners through...
Mathematics Assessment Project
Inscribing and Circumscribing Right Triangles
High schoolers attempt an assessment task requiring them to find the radii of inscribed and circumscribed circles of a right triangle with given dimensions. They then evaluate provided sample responses to consider how to improve...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Mt. San Antonio Collage
Circles
Don't circle around the topic, but get right to the center with tons of practice regarding circles in geometry. The note-incorporated worksheet provides guided practice through many topics such as central angles, inscribed polygons...
Illustrative Mathematics
Coins in a Circular Pattern
What starts as a basic question of division and remainders quickly turns abstract in this question of related ratios and radii. The class works to surround a central coin with coins of the same and different values, then develops a...
Illustrative Mathematics
Seven Circles III
A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...
Illuminations
Circumference and Areas of Circles
Middle and high schoolers listen to a scenario about a puppy and use the scenario to develop formulas in order to find the area of a circle. In this circumference lesson, pupils understand how to find the radius, diameter, area of a...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
Curated OER
Circles-Diameter, Circumference, Radius and the Discovery of Pi
Seventh graders measure the diameter, circumference and radius of a circle and find pi using the diameter and circumference. In this geometry lesson, 7th graders work in groups to find the diameter, radius, and circumference of circles....
Curated OER
Find Radius of the Circles
In this finding the radius of circles instructional activity, learners must calculate the radius of 4 circles. Students are given diameter and must write the radius on the line for each circle.
101 Questions
Coins in a Circle
Round and round you'll go! Learners watch as different-sized circles fill with coins. They collect data and then make a prediction about the number of coins that will fit in a large circular rug.
Curated OER
Circle Circus
Third graders find the radius and diameter of a bubble. In this radius and diameter instructional activity, 3rd graders create bubbles on their desk and find the radius and diameter of the bubble. Students work in partners to define...
Curated OER
Circles
In this circles instructional activity, 10th graders solve and complete 20 different problems related to various circles. First, they find the radius and diameter of a circle with a given circumference. Then, students determine the...
Curated OER
Circumferences, Diameters, and Radii
Learners explore circumferences, diameters, and radii. In this math lesson plan, students measure circumferences in inches and compute radii and diameters, given different circumferences.
Illustrative Mathematics
Tangent to a Circle From a Point
Learners see application of construction techniques in a short but sophisticated problem. Combining the properties of inscribed triangles with tangent lines and radii makes a nice bridge between units, a way of using...
Curated OER
Quiz: Area of a Circle
Geometers test their mastery at finding the area of a circle with 10 basic problems. Circle diagrams show line segments, points, and diameter. Distance of radii are given. They use pi as 3.14 to calculate the area. No answer key is...
Curated OER
Circles and Cylinders
In this geometry lesson, 10th graders break down a circle and identify the different parts. They discuss chords, diameter, radius, circumference, major and minor segment. There are 42 problems broken down into 5 different sections.
Flipped Math
Circles and Arc Lengths
Discuss all things round and round. Pupils review finding area and the circumference of circles and use them to solve problems. Next, they learn about central angles and their relationships to measures of arcs. Learners then find out how...
Curated OER
Diameter, Radius and Area
Students calculate the diameter, radius and area of a circle. In this geometry instructional activity, students investigate the different ratios of a circle. They calculate the surface are of each circle.
Virginia Department of Education
Going the Distance
Estimate the value of one of the most famous irrational numbers. The hands-on instructional activity instructs classmates to measure the circumference and diameters of circles using yarn. The ratio of these quantities defines pi.
Curated OER
Measuring the Area of a Circle
When mathematical errors happen, part of the learning is to figure out how it affects the rest of your calculations. The activity has your mathematicians solving for the area of a circular pipe and taking into consideration any errors...
Mathed Up!
Area and Circumference of Circles
Don't go around and around, help your class determine amounts around and in a circle with a video that connects circumference to the perimeter or the distance around an object. The resource includes 14 questions dealing with circles and...